1. Field of the Invention
The present invention relates to a wobble device for a hand-held power tool including a drive member rotatable about a drive axis, a driven member oscillatingly pivotable about a wobble axis, and a wobble bearing for connecting the driven member with the drive member. The wobble bearing has a drive-side bearing region with a drive-side guide circumferentially arranged about a drive axis and provided on the drive member, and a driven-side bearing region with a driven-side guide circumferentially arranged about the drive axis and provided on the driven member. The wobble bearing further includes roll elements guided simultaneously in both guides.
2. Description of the Prior Art
The wobble devices of the type discussed above are often used in hammer drills for converting a rotational movement of a spindle drive in a reciprocating linear movement of a driving piston. The driving piston drives a striker that applies a pulsed impact energy to a working tool holder.
German Publication DE 34 27 342 A1 discloses a hammer drill with a wobble drive for driving an air-cushion percussion mechanism. The wobble drive has drum press-fit on an intermediate shaft and having a spherical outer surface in which a circumferential groove is formed. The wobble drive further includes an annular wobble plate on the inner side of which an outer circumferential groove is formed. A ball is provided between the two grooves, which is simultaneously guided in both grooves.
The wobble drive described above is subjected, during operation, to a relatively high load, in particular, to pulsed reaction forces which are generated during operation of the percussion mechanism. On the other hand, the bearing region should be dimensioned so that mounting of the drive member, the driven member, and of the roll elements, which are arranged therebetween, is possible. Therefore, breaking of material, in particular, in the region of the guide can take place. The breaking of material noticeably reduces the service life of the wobble drive.
Accordingly, an object of the invention is a wobble drive having an increased service life.
Another object of the invention is a wobble drive in which its high stability is insured.